1. Field of the Invention
This invention relates to sample measurments, and more particularly, to measuring an object substance within a sample by generating and detecting an agglomeration reaction of microcarriers by specific coupling, such as an antigen-antibody reaction or the like.
2. Description of the Prior Art
A method of measuring an object substance within a sample with high accuracy utilizing a reaction of specifically coupling to the object substance, for example, an antigen-antibody reaction, so-called immunoassay, has been known. In one method, a reagent having a predetermined concentration containing a substance (for example, a monoclonal antibody), which is specifically coupled to an object substance (for example, a paticular antigen), adhered to the surfaces of carriers (for example, latex particles), serving as insoluble fine particles, is prepared. The reagent is mixed with a sample, such as serum or the like, to agglomerate the carriers by an antigen-antibody reaction, and so-called incubation is performed wherein the carriers are left alone for a time period (usually, about 20-30 minutes) to allow a sufficient agglomeration reaction at a constant temperature. Subsequently, the object antigen in the serum is qualitatively or quantitatively measured by measuring the agglomeration state of the carriers mainly by an optical method. This method is described in detail in, for example, Japanese Patent Public Disclosure (Kokai) Nos. 53-24015 (1978), 54-108693 (1979), 54-108694 (1979), 54-108695 (1979), 54-109494 (1979), 55-159157 (1980) and 62-81567 (1987).
In the above-described conventional method, however, in the process wherein the carriers agglomerate to form clumps in incubation, contact between respective carriers is mainly caused by the Brownian movement of the carriers themselves. Hence, particularly when the concentration of the carriers in a reaction fluid is low, the reaction is inefficient, and much time is needed.